Want to get these out before sleepin:
Find the limit, or show it doesn't exist:
\lim_{(x,y)\to(0,0)} \dfrac{x^3+y^3}{x^2-y^2}
The usual tricks like factorising/cancelling, going polar, x=y, x=0, y=0 don't seem to work? Probs blanking out. I know it doesn't exist but I can't find a path which...